基于有限冲击响应滤波器线性相移控制的单相系统数字锁相环

A Digital Phase-Locked Loop Based on the Linear Phase-Shifted Control Implemented by a Finite Impulse Response Filter for a Single-Phase Power System

利用有限冲击响应数字滤波器具有线性相移的特性,针对单相并网系统提出了基于有限冲击响应数字滤波器构造αβ静止坐标系下的电压矢量方法。参照三相并网系统基于αβ静止坐标系到dq同步旋转坐标系的数字锁相环原理,采用同步采样技术确保滤波器恒定系数的方法,实现了基于虚拟两相直角坐标系的数字锁相环控制。利用PSIM软件对电网电压幅值和频率的波动、3次谐波注入等参数变化的影响做了仿真研究。在此基础上,搭建了基于DSP TMS320C32为控制核心的模拟装置,实验结果验证了该方法是可行的,并且具有较好的动静态性能。

A finite impulse response （FIR） filter can guarantee the linear phase characteristics; therefore the method of constructing two voltage vectors vα, vβ, in the αβ stationary reference based on a FIR filter is proposed in this paper. According to the principle of the digital phase-locked loop （DPLL） by means of the transformation from ctl3 stationary reference to dq synchronously rotating reference for a three-phase system, and the synchronously sampling technique is used to assure the constant filter order, a DPLL on the basis of a fictitious two-phase transformation for a grid-connected single-phase power conversion system is implemented. Taking some parameters such as the fluctuations of the voltage magnitude and grid frequency and the 3^rd harmonic content into consideration, the proposed method is simulated in PSIM software. A simulative inverter with the control core of DSP TMS320C32 is installed. The experimental results verify that the method is feasible and it has the better static and dynamic performances.